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A 0.004 M solution of sodium sulphate is isotonic with 0.01M solution of glucose at same temperature. Calculate the degree of dissociation of sodium sulphate 

Posted by Meenakashi Chawla (May 25, 2017 11:13 a.m.) (Question ID: 5481)

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  • Ans.
    Answered by Payal Singh (May 25, 2017 4:32 p.m.)
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Why nitrogen is filled in  the  cyllinders of scuba divers if it blocks our capillaries.

Posted by Deepanshu Banga (May 23, 2017 12:18 p.m.) (Question ID: 5444)

Explain the reason of depresion in frezing point

Posted by Pawan Kabdal (May 22, 2017 4:55 p.m.) (Question ID: 5431)

  • Answers:
  • Freezing point depression is the phenomena that describes why adding a solute to a solvent results in the lowering of the freezing point of the solvent. When a substance starts to freeze, the molecules slow down due to the decreases in temperature, and the intermolecular forces start to take over. The molecules will then arrange themselves in a pattern, and thus turn into a solid. For example, as water is cooled to the freezing point, its molecules become slower and hydrogen bonds begin to "stick" more, eventually creating a solid. If salt is added to the water, the Na+ and Cl- ions attract to the water molecules and interfere with the formation of the large network solid known as ice. In order to achieve a solid, the solution must be cooled to an even lower temperature.

    The freezing point depression can also be explained in terms of vapor pressure. Adding solute to a solvent will essentially dilute the solvent molecules, and according to Raoult's law, this leads to a decrease in vapor pressure. Considering the fact that the vapor pressure of the solid and liquid forms must be the same at freezing point, because otherwise the system would not be at equilibrium, the lowering of the vapor pressure leads to the lowering of the temperature at which the vapor pressures of the liquid and frozen forms of the solution will be equal.

     

     The freezing point depression can be calculated by the formula:

    {tex}\Delta T_f=i\times K_ f\times molality{/tex}

    In this equation,

    {tex}\Delta T_f{/tex} is the freezing point depression,

    Kf is the freezing point depression constant,  and i is the van 't Hoff factor.

    The freezing point depression constant changes depending on the solvent, and the van 't Hoff factor accounts for the number of particles that a dissolving solute creates in solution.

     

    Answered by Payal Singh (May 23, 2017 11:07 a.m.)
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The number of tetrahedral voids present on each body diagonal in ccp unit cell is 

 

Posted by Muskan Asthana (May 09, 2017 12:04 p.m.) (Question ID: 5169)

  • Answers:
  • 2 tetrahedral voids on each body diagonal in ccp unit

    Total 8 tetrahedral voids in 1 ccp unit

    Answered by Aashka Shah (May 09, 2017 2:17 p.m.)
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CsBr crytal has bcc structure,

It has an edge length of 4.3 Å

The shortest interionic distance between Cs+ and Brions is

_-Pl. explain with soln

Posted by Aashka Shah (May 08, 2017 11:25 a.m.) (Question ID: 5159)

  • Answers:
  • Solution: 

    rc + ra = {tex}\sqrt 3a\over 2{/tex}

    => {tex}r_c + r_a = {\sqrt 3 \times 4.3\over 2}{/tex}{tex}3.72 A^°{/tex}

    Answered by Payal Singh (May 08, 2017 11:39 a.m.)
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  • IUPAC  name of potassium cuprochloride is? 
  • In 0.2 molal hcl calculate the no of hydroxyl ion in 10cmsolution... 
  • Which product is obtained     When auric chloride react with sodium chloride 
  • silver chloride is soluble in methyl amine due to formation of...
  •  

 

 

Posted by MUDASSIR MOHIUDDIN INAMDAR (May 05, 2017 6:09 p.m.) (Question ID: 5125)

  • Answers:
  • Solution: 

    {tex}AuCl_3 + NaCl \to Na[AuCl_4]{/tex}

     

    Silver chloride dissolves in methyl amine solution because it forms soluble complex.

    {tex}2CH_3NH_2 + AgCl \to {/tex}

    {tex}[CH_3 -H_2N \to Ag \leftarrow NH_2-CH_3]Cl{/tex}

    Answered by Payal Singh (May 05, 2017 7:17 p.m.)
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  • Molality  of NaOH is 1.25,percent by weight of NaOH  is,
Posted by MUDASSIR MOHIUDDIN INAMDAR (May 04, 2017 10:56 p.m.) (Question ID: 5121)

osmotic pressure is 4.6 of NaCl temp. Is 300 k calculate its degree of dissociation

R=0.082

Posted by Pavani B (May 02, 2017 5:03 p.m.) (Question ID: 5083)

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  • Ans.
    Answered by Payal Singh (May 02, 2017 5:17 p.m.)
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What is the atomic no of potassium?

Posted by ADITYA CHAKRABORTY (Apr 29, 2017 6:56 a.m.) (Question ID: 5060)

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  • Atomic number of potassium is 19.

    Answered by RAJENDRA SINGH (Apr 29, 2017 8:01 p.m.)
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What are the Characteristics of amorphous solids ?

Posted by Ankur Majumdar (Apr 23, 2017 8:56 a.m.) (Question ID: 5003)

  • Answers:
  • AMORPHOUS SOLIDS :-

    • It has irregular shape
    • isotropic in nature
    • has short range order
    • they are pseudo solids or super-cooled liquids
    • When cut with a specific sharp edge tool, they cut into two pieces with irregular surfaces 
    Answered by Aashka Shah (Apr 23, 2017 11:54 a.m.)
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Silver has atomic radius of 144pm and density of silver is 10.6 g cm3. To which type of cubic crystal silver belongs? 

Posted by Hritika Jain (Apr 21, 2017 10:44 a.m.) (Question ID: 4978)

  • Answers:
  • But the question is this much only and is from vibrant academy

    Answered by Hritika Jain (Apr 25, 2017 10:08 a.m.)
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But if we look like Fe<font size="2">2+ </font>as Cr and

Fe<font size="2">3+</font> as V

in that sense then Fe<font size="2">2+</font> should be the correct,,,,

is my method correct?????

My actual doubt was 

which is having maximum number of unpaired electron

Fe<font size="2">2+</font> or Fe<font size="2">3+                      </font>

Posted by Aashka Shah (Apr 19, 2017 9:52 p.m.) (Question ID: 4954)

  • Answers:
  • No ur method is not correct. Because electrons removed from outermost shell that is 4s in case of Fe.

    Answered by Payal Singh (Apr 20, 2017 3 p.m.)
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which is having maximum number of unpaired electron

Fe2+   or   Fe3+

Posted by Aashka Shah (Apr 19, 2017 1:33 p.m.) (Question ID: 4946)

  • Answers:
  • But if we look like Fe2+  as Cr  and

    Fe3+ as V

    in that sense then Fe2+ should be the correct,,,,

    is my method correct?????

    Answered by Aashka Shah (Apr 19, 2017 5:13 p.m.)
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  • Electronic Configuration of

    Fe = {tex}1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2{/tex}

    Electronic Configuration of

    Fe2+  = {tex}1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 {/tex}

    Electronic Configuration of

    Fe3+ = {tex}1s^2 2s^2 2p^6 3s^2 3p^6 3d^5{/tex}

    So Fe3+ has more unpaired electron. 

    Answered by Payal Singh (Apr 19, 2017 4:38 p.m.)
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Can anyone give me any trick to remember d & f block elements easily

pl. reply fast its urgent 

 

Posted by Aashka Shah (Apr 18, 2017 7:41 p.m.) (Question ID: 4939)

  • one conformation not elements but the whole chapter with highlights or anything if someone could help me with it

    Posted by Aashka Shah (Apr 18, 2017 7:42 p.m.)
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How to convert galvanic cell into electrolytic cell? 

Posted by Pallavi Kapoor (Apr 18, 2017 6:27 p.m.) (Question ID: 4937)

Write explanation of galvanic cell? 

Posted by Pallavi Kapoor (Apr 18, 2017 6:26 p.m.) (Question ID: 4936)

What is the difference between amorphous and crystalline solids on the basis of cleavage?

Posted by Ankur Raj Singh (Apr 15, 2017 8:45 p.m.) (Question ID: 4892)

  • Answers:
  • Amorphous solids don't break at fixed cleavage planes whereas Crystalline solids cleavage along particular direction at fixed cleavage planes.

    Answered by Payal Singh (Apr 17, 2017 6:39 a.m.)
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What is kernals

Posted by Dev Lavania (Apr 13, 2017 3:53 p.m.) (Question ID: 4865)

  • Answers:
  • Kernels are basically the atom without its valence shell .all the inner shells and the nucleus make up the kernel. The valence shell is represented outside the kernel.

    Answered by Payal Singh (Apr 17, 2017 6:54 a.m.)
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What product is formed when 1-bromo-2-chlorocyclobutane combines with sodium /ether 

Posted by Swastika Chandan (Apr 12, 2017 5:34 p.m.) (Question ID: 4860)

  • Answers:
  • This is example of Wurtz Reaction . Product ll be Bicyclobutane.

    Answered by Payal Singh (Apr 17, 2017 5:51 p.m.)
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Why enthalpy of mixing and volume of mixing of the pure components to form the solution is zero?

Posted by Pallavi Kapoor (Apr 11, 2017 9:12 p.m.) (Question ID: 4841)

  • Answers:
  • The standard enthalpy of formation for an element in its state is zero.

    Answered by Swastika Chandan (Apr 12, 2017 5:43 p.m.)
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What are the  7 types of unit cells? 

 

Posted by Mahendra bagul (Apr 11, 2017 4:57 p.m.) (Question ID: 4834)

  • Answers:
  • Solution

    Answered by Payal Singh (Apr 27, 2017 5:17 a.m.)
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Electrochemistry is the study of production of electricity from

<hr/>

<input id="option_198136" name="option" ng-click="selectedOption(practiceData[counter].id, option.id)" ng-disabled="showResult" type="radio"/><label dynamic="option.option" for="option_198136">nuclear energy and the use of heat energy to bring about non-spontaneous chemical transformations</label>

<input id="option_198133" name="option" ng-click="selectedOption(practiceData[counter].id, option.id)" ng-disabled="showResult" type="radio"/><label dynamic="option.option" for="option_198133">energy released during spontaneous chemical reactions and the use of electrical energy to bring about non-spontaneous chemical transformations</label>

<input id="option_198135" name="option" ng-click="selectedOption(practiceData[counter].id, option.id)" ng-disabled="showResult" type="radio"/><label dynamic="option.option" for="option_198135">energy released during spontaneous chemical reactions and the use of heat energy to bring about non-spontaneous chemical transformations</label>

<input id="option_198134" name="option" ng-click="selectedOption(practiceData[counter].id, option.id)" ng-disabled="showResult" type="radio"/><label dynamic="option.option" for="option_198134">nuclear energy and the use of electrical energy to bring about non-spontaneous chemical transformations</label>

Posted by ashish jaiswal (Apr 10, 2017 10:32 p.m.) (Question ID: 4821)

The unit cell cube length for LiCl is 5.14angstrom . Assuming anion-anion contact, calculate the ionic radius for chloride ion.

Posted by Devansh Agarwal (Apr 10, 2017 7:53 p.m.) (Question ID: 4817)

Why people suffer from anoxia at high altitudes 

Posted by Abhishek Verma (Apr 10, 2017 10:04 a.m.) (Question ID: 4808)

  • Anoxia is a condition characterized by an absence of oxygen supply to an organ or a tissue.Anoxia results from a decrease in the amount of hemoglobin or RBCs in the blood, which reduces the ability to get oxygen to the tissues 

    Posted by Ayush Saini (Apr 10, 2017 10:58 a.m.)
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  • Answers:
  • according to henry's law the vapour pressure of gas is directly proportional to the concentration of gas or we can say the mole fraction of gas in the slution

    At higher altitude the vapour pressure of oxygen decreases , which reults in the lowering of concentration of oxygen in our blood and results in anoxia

    Answered by Payal Singh (May 20, 2017 5:06 p.m.)
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How more the rate constant & more will rate of reaction.

Posted by Vaalee Patil (Apr 09, 2017 6:30 p.m.) (Question ID: 4797)

1)How to calculate valency?  2)How to identify the whether it is a covalent or ionic compound ? 3)Is there any shortcut for to tell hybridisation? 4)How to calculate the l0ne pairs and bond pairs ?

Posted by doreamon superman (Apr 07, 2017 7:40 p.m.) (Question ID: 4768)

As the number of holes are equal to number of free electrons...

Plzz send me answers 

Posted by Yash Sharma (Apr 05, 2017 6:04 p.m.) (Question ID: 4728)

Why holes are majority carrier in p-type semiconductors 

Posted by Yash Sharma (Apr 05, 2017 6:02 p.m.) (Question ID: 4727)

  • Answers:
  • When intrinsic semiconductors like Si and Ge are doped with group-13 elements like B,Al or Ga which contains only three valence electrons, then the place where the fourth valence electron is missing is called electron hole.An electron from a neighbouring atom can come and fill the electron hole,but in doing so it would leave an electron hole at its majority position.

    Since, the number of holes are more than the number of electrons,therefore they are called as p-tyoe semiconductors and holes are the majority carriers.

     

    Answered by Shweta Gulati (Apr 07, 2017 12:11 p.m.)
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Which type of solid is libr , brass , (nh4)3po4 , 

Posted by Rohan Choudhary (Apr 01, 2017 10:03 a.m.) (Question ID: 4644)

  • Answers:
  • Solution : LiBr is Ionic, Brass is metallic, 

    (NH4)3PO4  is ionic.

    Answered by Payal Singh (Apr 01, 2017 10:51 a.m.)
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is p4h10 molecular solid

Posted by Rohan Choudhary (Apr 01, 2017 10 a.m.) (Question ID: 4643)

  • Answers:
  • Ans. Yes it is molecular 

    Answered by Payal Singh (Apr 01, 2017 10:46 a.m.)
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